This invention relates to a method and apparatus for regulating the volume flow rate of a fluid including a solution. More specifically the invention concerns providing apparatus for accurately measuring and controlling the rate of flow of a solution and providing solution flow control in response to process operation and overflow or underflow conditions.
In the production of magnet wire an insulation layer is often applied to the exterior of the magnet wire such that the wire may subsequently be wound into its end use configuration having adjacent turns and layers in which the insulation layer providing electrical insulation between adjacent turns and layers. In order to provide such a wire it has been common to provide a coating having insulating properties which is applied to the exterior of the wire.
Additionally since the magnet wire is wound into a tightly wrapped configuration such as an electric motor stator or a solenoid or other coil, the wire needs a lubricant on its exterior surface to promote handling of the wire while reducing the potential for wire breakage. The applicator described herein is capable of both applying a lubricant solution to a moving wire as well as applying an insulating coating thereto.
One method of applying either a lubricant or an insulating enamel to magnet wire is to have a moving wire pass through a felt applicator. Lubricant or enamel is wicked upwardly from a reservoir of solution to the felt immediately adjacent the wire and transferred from the felt to the wire to apply the coating. The amount of solution supplied by the felt to the wire is based on the wicking ability of the felt and the distance between the solution and the wire through which the solution must be wicked. The height of the reservoir of solution in contact with the felt applicator determines the distance between the reservoir of solution and the wire to be coated. The distance therebetween controls the amount of solution being applied to the wire. Variants in the height level of the solution affects the thickness of the coating applied.
Prior art systems have attempted to regulate the amount of solution supplied to the reservoir using an automotive type carburetor. A reduced diameter orifice is fed and controlled by a float valve within the carburetor. It has been found however that the oscillation and flow from the carburetor based upon a control from the float valve is such that the height of the reservoir rises and falls creating a variance in the amount of solution applied to the exterior surface of the wire.
Another method of regulating the height of the reservoir is to utilize a float valve mounted in the reservoir to travel upwardly and downwardly as the height of the reservoir rises and falls. It has been found that such a valve lacks the sensitivity needed to accurately control the desired height of the reservoir.
The herein apparatus utilizes a highly sensitive flow meter and a precision valve such that the rate of flow of solution may be controlled very accurately. In this manner the rate of flow of solution to the reservoir is controlled to thereby control the rate of application of the solution from the reservoir to the wire. In addition a solenoid valve is provided such that flow to the reservoir is interrupted if the wire manufacturing process is stopped. In this manner no excess solution is supplied to the tank during those intervals when the wire is not being drawn through the applicator. Additionally, a float valve is provided as a safety means for indicating either high or low levels in the reservoir. This float valve may be utilized to deenergize the solenoid preventing further solution flow to the reservoir if a high level of solution in the reservoir is detected and to energize an alarm of a low level of solution in the reservoir is detected.